CRCP: a Cloud Resolving Convection Parameterization for modeling the tropical convecting atmosphere

A new computational approach, CRCP, is proposed in which both the large-sca le (LS) tropical dynamics and cloud-scale (CS) dynamics are captured explic itly. The leading idea is to represent subgrid scales of the LS model by im bedding a 2D CS model in each column of the 3D LS model - the approach tail ored for distributed memory architectures. The overall philosophy underlyin g CRCP is the reinvestment of efforts from large-eddy simulation to elabora te yet 'embarrassingly parallel' turbulence models. Similar as in the tradi tional 'convection parameterization', the LS model provides 'ambient forcin gs' for the CS model imbedded inside each LS column, and the CS model feeds back a 'convective response' for every column of the LS model. Furthermore , availability of the cloud-scale data allows for explicit coupling of mois t convection with radiative and surface processes. Following our experience with cloud-resolving modeling of the tropical convection, the CS model is oriented along the E-W direction inside each LS model column. A simple stra tegy for the coupling the LS and CS models derives from physical understand ing of interactions between LS flow and moist tropical convection. Theoreti cal considerations are illustrated with an example of application to observ ational data from the Phase III of the Global Atmospheric Research Programm e Atlantic Tropical Experiment (GATE). (C) 1999 Elsevier Science B.V. All r ights reserved.